Mesoplodont whale
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 Sowerby's Beaked Whale (on Faroese stamp)
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Mesoplodont whales are fourteen species of whale in the genus Mesoplodon, making it the largest genus in the cetacean order. Two species were described as recently as 1991 (Pygmy Beaked Whale) and 2002 (Perrin's Beaked Whale), and marine biologists predict the discovery of more species in the future. They are the most poorly known group of large mammals. The word mesoplodon comes from the Greek meso- (middle) - hopla (arms) - odon (teeth), and may be translated as 'armed with a tooth in the centre of the jaw'.
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[edit] Species
English name (most common first), Latin name:
- Sowerby's Beaked Whale M. bidens
- Andrews' Beaked Whale M. bowdoini
- Hubbs' Beaked Whale M. carlhubbsi
- Blainville's Beaked Whale M. densirostris
- Gervais' Beaked Whale M. europaeus
- Ginkgo-toothed Beaked Whale M. ginkgodens
- Gray's Beaked Whale M. grayi
- Hector's Beaked Whale M. hectori
- Layard's Beaked Whale M. layardii
- True's Beaked Whale M. mirus
- Perrin's Beaked Whale M. perrini
- Pygmy Beaked Whale M. peruvianus
- Stejneger's Beaked Whale M. stejnegeri
- Spade-toothed Whale M. traversii
Longman's Beaked Whale (also known as the Indo-Pacific Beaked Whale) is also sometimes classed in the Mesoplodon genus. However, most authorities follow the lead of Joseph Curtis Moore who in the 1960s put it in its own genus - the Indopacetus.
[edit] Physical description
Beaked whales are typically medium to large sized for toothed whales, 3 to 6 meters in length, but diminutive when compared with Bottlenose Whales and Giant Beaked Whales. The females are the same size or larger than males in every species, but the males typically have a bolder coloration and a unique dentition. The lower jaw often forms a huge arch in some species, sometimes extending above the rostrum in a shape comparable to a playground slide. Every species has large (sometimes tusk-like) teeth of variable size, shape, and position. Gray's Beaked Whale is the exception and has numerous small and possibly functional teeth in the lower jaw. The males of most species are covered in scars from the teeth of other males. Both genders often have bites from cookie-cutter sharks. The dorsal fin is rather small and far between two-thirds and three-quarters down the back of the animal. Information on longevity and lactation is not existent, and information on gestation is nearly so.
[edit] Behavior
Most species are very uncommonly observed, and little is known about their behavior. They are typically found in groups, possibly segregated between genders. Some species are so uncommon that they have yet to be observed alive. On the surface they are typically very slow swimmers and do not make obvious blows. They have never been observed raising their flukes above the water either. They are all very deep divers, and typically feed entirely on squid.
[edit] Conservation
The Mesoplodonts are completely unknown as far as population estimates are concerned. They have been hunted occasionally by the Japanese, but never directly. They are also accidentally captured in drift nets. It is not known what effect this has on the population.
[edit] References
- Encyclopedia of Marine Mammals. Edited by William F. Perrin, Bernd Wursig, and J.G.M Thewissen. Academic Press, 2002.
- Sea Mammals of the World. Written by Randall R. Reeves, Brent S. Steward, Phillip J. Clapham, and James A. Owell. A & C Black, London, 2002.
